In a linear guiding portion or a curvilinear guiding portion of a work table of a machine tool or any one of various conveying devices, there is heavily used a motion guide device in which a moving block having a movable member such as a table mounted thereon is continuously moved along a track rail. In the motion guide device of this type, the moving block is assembled to the track rail through intermediation of a large number of balls or rollers (hereinafter referred to as “rolling elements”). The rolling elements roll between the moving block and the track rail while applying a load, to thereby enable easy motion of the movable member, which is mounted on the moving block, along the track rail with an extremely small resistance. Further, the moving block includes an endless circulation path for the rolling elements. The rolling elements are circulated in the endless circulation path, to thereby enable continuous movement of the moving block along the track rail.
In the motion guide device configured as described above, depending on the usage environment, foreign matters such as chips of a workpiece or refuse may adhere to the track rail. If those foreign matters enter the moving block running along the track rail, flaws may be generated in a rolling surface of the track rail, a load rolling surface of the moving block, or the rolling elements, or abrasion of those members may be accelerated. As a result, a movement accuracy of the moving block in the motion guide device may be impaired in an early stage. Further, when a coolant used for cooling a workpiece in the machine tool enters the moving block via the track rail, lubricating oil adhering to the surface of the rolling element may be washed out, which may also cause abrasion of the rolling surfaces and the rolling elements in an early stage.
For such reasons, generally, a pair of end seal members are mounted to the moving block at both ends in a moving direction thereof. Each of the end seal members includes an end seal portion which comes into sliding contact with the surface of the track rail, and when the moving block moves along the track rail, the end seal portion wipes the matters adhering on the track rail off the surface of the track rail, thereby preventing the adhering matters from entering the moving block (Patent Literature 1).
Further, in some cases, in order to reliably prevent fine adhering matters from entering the moving block, a plurality of overlapped end seal members are mounted on the end portion of the moving block. That is, in a conventional motion guide device, the matters adhering on the track rail are removed by the end seal member along with the passage of the moving block, and by increasing the reliability of the removal, the adhering matters are prevented from entering the moving block.